A traditional Chinese medicine manufacturing technique using a medicinal herb processing technique is called “Po-je”, “Hap-hwa”, “Hap-yak”, “Su-chi”, “Po-ja”, “Beob-je” and “Su-sa” in Korean. This medicine manufacturing technique comprises changing the inherent properties of medicinal herbs by processing the medicinal herbs on the basis of Chinese medicine theory.
The objects of processing medicinal herbs are to clarify medicine, facilitate the storage of medicines, reduce or remove the toxicity or side effects of medicines, change the properties of medicines to make the medicines more effective, enhance the therapeutic effects of medicines, and eliminate offensive odors and tastes of medicines to facilitate the intake of the medicines.
In the manufacture of cosmetic products, raw materials having various effects, including skin whitening, wrinkle reduction and skin protection, are screened and added. An antioxidant effect removes reactive oxygen species, which are the cause of skin aging, to retard or prevent skin aging, makes a dark and inelastic skin fresh and clear, and makes the skin appear healthy. However, only a limited number of materials are known to have the antioxidant effect, and only a small number of the materials that are currently used are chemically synthesized.
The skin functions as an important barrier to protect the body from external factors. The barrier function is a protective function to defend the body from various external stimuli, for example chemicals, atmospheric pollutants, dry environments and UV rays, and to prevent anexcessive loss of water from the body through the skin. This protective function can be maintained when the horny layer consisting of keratinocytes is maintained in a normal state.
The horny layer (stratum corneum), which is the outermost layer of the epidermis, is formed from keratinocytes and consists of differentiated keratinocytes and lipid layers surrounding these keratinocytes (Marcelo C. L. et al, J. Invest. Dermatol., 80, pp 37-44, 1983).
Keratinocytes are characteristic cells formed as a result of a process in which basal cells that continuously proliferate in the basal layer of the epidermis are pushed up to the surface of the skin while undergoing gradual changes in their shape and function. After the passage of a given period of time, old keratinocytes are shed from the skin's surface, and new keratinocytes function in place of the shed cells. This repeated and serial process is called differentiation or keratinization of epidermal cells.
Further, during the keratinization process, keratinocytes produce natural moisturizing factors (NMFs) and intracellular lipids (ceramides, cholesterols, fatty acids, etc.) while forming a horny layer, which impart solidity and flexibility to the horny layer that consequently will function as the skin barrier.
However, the horny layer is highly susceptible to functional loss by various factors, for example living and behavioral factors such as excessive face washing and bathing, environmental factors such as dry atmosphere, contaminants, etc., and endogenous disorders such as atopic dermatitis and senile pruritus. With recent substantial increases of various harmful factors, the number of patients who complain of dry skin conditions and consequential disorders has gradually increased.
Accordingly, various studies focused on supplying water from an external source or preventing the loss of water from the body to maintain the skin's water content at a suitable level have been conducted, and various moisturizers having water-holding capacity have been developed. Lipid components such as ceramides, and materials capable of increasing water retention in the horny layer, such as essential fatty acids and lipid complexes, are generally used as skin moisturizers (Rawlings A. V. et al, J. Invest. Dermatol., 5, pp 731-741, 1994).
However, currently, factors harmful to the skin are gradually increasing, production and shedding rates of the horny layer are becoming slower due to a change of eating habits, and the amount of moisturizing factors and lipids is decreasing due to deterioration in the function of keratinocytes. For these reasons, more people have a skin whose horny layer does not exhibit a normal skin barrier function. This deterioration of the skin barrier function leads to various skin diseases, including xerosis cutis, a topic dermatitis, contact dermatitis and psoriasis. Although such diseases can be alleviated with conventional moisturizers having water-holding capacity, the diseases are difficult to fundamentally cure.
Recently, various cosmetic products that employ natural materials in order to reduce skin irritation caused by various chemical substances have been developed. In addition, natural materials having reduced side effects on the skin receive a great deal of attention from consumers. Thus, many efforts are being made to develop natural materials useful as cosmetic raw materials.